1. Technical Field
The disclosure relates in general to a semiconductor structure, and more particularly to a semiconductor structure having a first isolation and a second isolation, wherein a ratio of a depth of the first isolation to a depth of the second isolation is smaller than 1.
2. Description of the Related Art
With the development of semiconductor technology, reduction of feature size, improvements of the rate, the efficiency, the density and the cost per semiconductor structure are the important goals in the semiconductor technology. High power devices have been applied as semiconductor elements. On-resistance (Ron) is one of key factors of the semiconductor device. The lower the on-resistance, the lower the power consumption of the semiconductor device.
In a general semiconductor structure, low on-resistance (Ron) and high breakdown voltage (BVD) are required. Many improvements have been disclosed by modifying the semiconductor structure, however, they usually need extra masks and more steps of process, such that the cost of manufacturing the semiconductor structure becomes higher.